Write the conversation response. Read the following conversation: +What are the mirrors in a Laser diode?. +In VCSELs, the mirrors are typically grown epitaxially as part of the diode structure, or grown separately and bonded directly to the semiconductor containing the active region.. +Are the mirrors the same for all types of laser diodes?. +VECSELs are distinguished by a construction in which one of the two mirrors is external to the diode structure.. +What are the different types of mirrors for?. +As a result, the cavity includes a free-space region.. +What is the distance of the mirrors?. +A typical distance from the diode to the external mirror would be 1 cm.. +Are there any other interesting aspects about this article?. +One of the most interesting features of any VECSEL is the small thickness of the semiconductor gain region in the direction of propagation, less than 100 nm.. +Is the laser diode always on?. +
In contrast, a conventional in-plane semiconductor laser entails light propagation over distances of from 250 µm upward to 2 mm or longer.